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Full text of "Communication-USB Linx SDM-USB-QS-SUSB Module Design Guide OCR"

t 



INTERFACE MODULE 

QS SERIES 



LINX 

mm TECHNOLOGIES 

nun 

SDM-USB-QS-S USB MODULE DESIGN GUIDE 
DESCRIPTION 




T 


„ 0.812" „ 


BLINX 


0.630" 


USB MODULE 




SDM-USB-QS-S 


i 


1 LOT 10000 




TOP VIEW 


o.i 25" r. 


f SIDEVIEW 



The Linx QS Series USB module allows the rapid 
addition of USB to virtually any device. Housed in 
a compact SMD package the QS module 
provides a complete solution for converting 
between USB and logic level serial sources. The 
module can be directly connected to virtually any 
serial device including microprocessors, 
RS232/RS485 level converters, or Linx wireless 
RF modules. The QS module is completely self 
contained and requires no external components, 
(except a USB jack) and includes all necessary 
firmware and drivers, freeing the designer from 
complicated programming. Power can be 
supplied externally or from the USB bus. Both Figure 1: Package Dimensions 
USB 1 .1 and USB 2.0 are supported at data rates 
to 3Mbps. 

FEATURES 

■ VID, PID, Serial Number, and 
Descriptors Programmed via USB 

■ No External Components Needed 
(Except a USB Jack) 

■ Compact Surface-mount Package 

■ Drivers and Firmware Included 

■ Supports Windows 98/2000/ME/XP 

■ USB 1 .1 and 2.0 Compatible 



■ Single Chip I 
Serial Data Conversion 

■ Low-Cost 

■ 3Mbps baud rate 

■ Supports Low-Speed USB 

■ Full Handshaking Support for 
RS232 and RS485 

■ Bus-or-Self Powered 

APPLICATIONS INCLUDE 

■ Interface / Upgrade Legacy Peripherals 

■ Interfacing Microcontrollers To USB 

■ USB-to-RS232 / RS485 Converters 

■ Interfacing RF Modules To USB 

■ USB Smart Card Readers 

■ USB Modems 

■ Robotics 

■ USB Instrumentation 

■ USB Game Controllers 

■ USB-to-Serial Converter Cables 



ORDERING INFORMATION 



PART* 


DESCRIPTION 


SDM-USB-QS-S 


USB Module 


MDEV-USB-QS 


Master Development Kit 



Revised 1/10/04 



Page 1 



ABSOLUTE MAXIMUM RATINGS 



Supply voltage Vqq 


-0.5 


to 


+6.0 VDC 


Max Current Sourced By Data Pins 




2 


mA 


Max Current Sunk By Data Pins 




4 


mA 


Operating temperature 





to 


+70 °C 


Storage temperature 


-40 


to 


+90 °C 


Soldering temperature 


+225°C for 10 seconds 


Any input or output Pin 


-0.5 


to 


V cc + 0.5 VDC 


•NOTE* Exceeding any of the limits of this section may 


lead to permanent 


damage to the device. Furthermore, extended operation at these maximum 


ratings may reduce the life of this device 









ELECTRICAL SPECIFICATIONS 





Designation 


:■ ■ .0 


Typical 


Max. 


Units 


Notes ' 


Operating Voltage 


v C c 


4.4 


5.0 


5.26 


VDC 




Supply Current 






26 


28 


mA 




UART SECTION 
Data Rate 




0.0003 




3 


Mbps 




Data Output 














Logic Low 


vol 


0.1 




0.7 


VDC 




Logic High 


v h 


4.4 




4.9 


VDC 




EEPROM Size 








1024 


Bits 




USB SECTION 
Data Output 














Logic Low 


uv OL 







0.3 


VDC 




Logic High 


uv 0H 


2.8 




3.6 


VDC 




Single Ended RX Threshold 




0.8 




2.0 


VDC 




Differential Common Mode 




0.8 




2.5 


VDC 




Differential Input Sensitivity 




0.2 






VDC 




ENVIRONMENTAL 










o ; ' a 




Operating Temperature Range 




6 




+70 


C 





A 



*CAUTION* 

This product incorporates numerous static-sensitive components. 
Always wear an ESD wrist strap and observe proper ESD handling 
procedures when working with this device. Failure to observe this 
precaution may result in module damage or failure. 



PIN ASSIGNMENTS 







1 


]USBDP 


RiC 


i 16 


2 


] USBDM 


DCDL" 


15 


3 


]GND 


DSR[ 


t 14 


4 


]VCC 


DATAJN [ 


3 13 


5 


] SUSPJND 


DATA_OUT [ 


1 12 


6 


] BXJND 


RTS[ 


I 11 


7 


]TX_IND 


CTSC 


I 10 


8 


]48S„TX 


DTR [ 


\ 9 



Figure 2: 
Page 2 



(Top View) 



PIN DESCRIPTIONS 



Pin# 


Name 


Description 


1 


USBDP 


USB data signal plus. 


2 


USBDM 


USB data signal minus. 


3 


GND 


Ground supply. 


4 


VCC 


Positive power supply. 


5 


SUSPJND 


Goes low during USB Suspend Mode. This pin can be used to 
power down external logic when the host puts the USB bus 
into suspend mode. 


6 


RXJND 


Xhic lino will milcp lr>\A/ uuhon ro/**pi\/inn rinta frnm thp I I^R hiiQ 

1 1 Mo III IC WIN jJUloC IUW VVIlCIl ICLfCSVIiiy UCtLCt IIUIII IMC UOU UUO. 

This allows for the connection of a LED indicator. 


7 


TXJND 


Thte linp will ni il^p Inw whpn trfln^mittinn riata nn thp 1 f SR 

1 1 ISO HI IC Will UUIoC IUW Wild 1 LIClllOiillLLiMy UCtlCt Ul i 11 iC Uuu 

bus. This allows for the connection of a LED indicator. 


8 


485_TX 


Transmit enable line for RS485 applications. 


9 


DTR 


Data Terminal Ready control / handshake output 


10 


CTS 


Clear To Send control / handshake input 


11 


RTS 


Request To Send control / handshake output 


12 


DATA_OUT 


Transmit asynchronous data output 


13 


DATAJN 


Receive asynchronous data input 


14 


DSR 


Data Set Ready control / handshake input 


15 


DCD 


Data Carrier Detect control / input 


16 


Rl 


Ring Indicator control input 



Page 3 



r 



PRODUCTION GUIDELINES 



The QS modules are packaged in a hybrid SMD package that supports hand or 
automated assembly techniques. Since QS modules contain discrete 
components internally, the assembly procedures are critical to ensuring the 
reliable function of the QS product. The following procedures should be reviewed 
with and practiced by all assembly personnel. 

PAD LAYOUT 

The following pad layout diagram is designed to facilitate both hand and 
automated assembly . 




HAND ASSEMBLY 



The QS module's primary mounting surface is sixteen pads located on the bottom of 
the module. Since these pads are inaccessible during mounting, castellations that 
run up the side of the module have 



Soldering Iron 
Tip\ 




PCB Pads 



Solder 



been provided to facilitate solder 
wicking to the module's underside. 
This allows for very quick hand 
soldering for prototyping and small 
volume production. 

If the recommended pad guidelines 
have been followed, the pads will 
protrude slightly past the edge of the , 
module. Use a fine soldering tip to Ftgure 4: QS Soldering Techmque 
heat the board pad and the castellation, then introduce solder to the pad at the 
module's edge. The solder will wick underneath the module providing reliable 
attachment. Tack one module corner first and then work around the device taking 
care not to exceed the times listed below. 



Absolute Maximum Solder Times 

Hand-Solder Temp. TX +225°C for 10 Seconds 
Hand-Solder Temp. RX +225°C for 10 Seconds 
Recommended Solder Melting Point +180°C 
Reflow Oven: +220°C Max. (See adjoining diagram) 



Page 4 



r 



AUTOMATED ASSEMBLY 



For high-volume assembly most users will want to auto-place the modules. The 
modules have been designed to maintain compatibility with reflow processing 
techniques, however, due to the their hybrid nature certain aspects of the 
assembly process are far more critical than for other component types. 

Following are brief discussions of the three primary areas where caution must be 
observed. 

Reflow Temperature Profile 

The single most critical stage in the automated assembly process is the reflow 
process. The reflow profile below should not be exceeded since excessive 
temperatures or transport times during reflow will irreparably damage the modules. 
Assembly personnel will need to pay careful attention to the oven's profile to 
ensure that it meets the requirements necessary to successfully reflow all 
components while still remaining within the limits mandated by the modules 
themselves. 



300 

c 

250 



200- 
Temperature 
150 

100- 

50. 





Ideal Curve 
Limit Curve 



Forced Air Reflow Profile 



210C 




^ Ramp-up 



120 150 180 210 240 270 300 330 360 
Time (Seconds) ^ 



Figure 5: Maximum Reflow Profile 

Shock During Reflow Transport 

Since some internal module components may reflow along with the components 
placed on the board being assembled, it is imperative that the modules not be 
subjected to shock or vibration during the time solder is liquid. 

Washability 

The modules are wash resistant, but are not hermetically sealed. Linx 
recommends wash-free manufacturing, however, the modules can be subjected 
to a wash cycle provided that a drying time is allowed prior to applying electrical 
power to the modules. The drying time should be sufficient to allow any moisture 
that may have migrated into the module to evaporate, thus eliminating the 
potential for shorting damage during power-up or testing. If the wash contains 
contaminants, the performance may be adversely affected, even after drying. 



Page 5 



MODULE DESCRIPTION 



The Linx SDM-USB-QS-S module will convert USB signals from a host, such as 
a PC or hub, into TTL logic level signals. This enables the module to be 
connected directly to microcontrollers (or Linx RF modules for wireless 
applications) or to RS232 or RS485 level converters for communication with 
legacy devices. The module handles all of the complicated enumeration and bus 
communication processes thus freeing the designer to focus on handling the 
data. All necessary firmware is included in the module and the device descriptors 
can easily be changed to customize the device. 

The host application software can access the USB device by simple custom 
functions or by standard Windows Win32 API calls. In addition, Virtual Com Port 
drivers are available that make the USB module appear to the PC as an 
additional COM port without the need for additional system resources, such as 
an IRQ or address. This allows the designer to program the application software 
to use standard serial or parallel ports and then to simply select the port that 
represents the USB module. The drivers will then automatically direct the data to 
the USB bus and the device. 

INSTALLING THE DRIVERS 

The drivers for the USB module are included with the module's 
development system or may be downloaded from the Linx web site 
(www.linxtechnologies.com). These drivers should be downloaded onto the hard 
drive of a PC or onto a disk. When the module is attached to the PC for the first 
time Windows will automatically detect the device and search for the best driver. 
The user will be prompted to provide a location for Windows to find the drivers, 
so the user will then browse to the folder or the disk, click Next and Windows will 
do the rest. Windows XP may return an error window shown in the figure below. 





hardware Installation 






f ^ The software you are instating 'orthis hardware. 






Unx LTUSB Device 






; : hasnct passed Windows Lagoiestngte venfyftsGanoBSibiicy 
with Windows: XP. ffel meWre.^'m- is ^nxs 11 ;.- 






(Continuing your installation of Ihts software may impair 
or destabilize the correct operation of your system 
either immediately or in the future. Microsoft strongly 
recommends that you stop this 'ink^^ier* now and 
contact the hardware vendor for software that has 
passed Windows Logo testing. 






^ J " 





Figure 6: Windows XP Driver Error Window 



This window is simply a warning that the driver has not gone through Microsoft's 
certification process and could potentially pose a problem for the system. The 
drivers provided for the QS module have been independently tested and should 
not pose any problems unless modified by the user. Click the Continue Anyway 
button to finish the installation process. 



Page 6 



THEORY OF OPERATION 



Figure 7 below shows a block diagram of the QS module. 



USBDP - 
USBDM - 



USB 
Transceiver 



-SUSPJND 



TX Buffer 
128 Bytes 



Serial Interface 
Engine (SIE) 



USB Protocol 
Engine 



UART FIFO 
Controller 



RX Buffer 
384 Bytes 




Clock 



Figure 7: SDM-USB-QS-S Block Diagram 

The USB transceiver block provides the physical interface for the USB signalling. 

The USB DPLL locks onto the NRZ data and provides separate recovered clock 
and data signals to the Serial Interface Engine (SIE). 

The SIE performs the parallel to serial and serial to parallel conversion, bit- 
stuff i ng/u n -stuff i ng , and CRC calculations on the USB data. 

The USB Protocol Engine manages the data from the USB control endpoint, the 
USB protocol requests from the USB host controller, and the commands for 
controlling the functional parameters of the UART. 

Data from the USB data out endpoint is stored in the TX buffer and removed from 
the buffer to the UART transmit register under control of the UART FIFO 
controller. 

Data from the UART receive register is stored in the RX buffer prior to being 
removed by the SIE on a USB request for data from the device data in endpoint. 

The UART FIFO controller handles the transfer of data between the RX and TX 
buffers and the UART transmit and receive registers. 

The UART performs asynchronous 7/8 bit parallel to serial and serial to parallel 
conversion of the data on the RS232 (RS422 and RS485) interface. Control 
signals supported by the UART include RTS, CTS, DSR , DTR, DCD and Rl. The 
UART provides a transmitter enable control signal (485_TX) to assist with 
interfacing to RS485 transceivers. The UART supports RTS/CTS, DSR/DTR and 
X-On/X-Off handshaking options. Handshaking, where required, is handled in 
hardware to ensure fast response times. The UART also supports the RS232 
BREAK setting and detection conditions. 



Page 7 



POWER SUPPLY GUIDELINES 



The USB module can be powered in two ways: from the USB bus or from an 
external source. If neccisary, a voltage regulator can be used to supply a clean 
5V as the external source, or the VCC pin can be connected to the bus power 
pin of the USB connector. Using the bus to power the module is an advantage 
because the module then uses power from the host rather than from the 
peripheral. This is especially helpful if the peripheral is battery powered. Figure 
8 shows the schematic for a bus powered device. 



USB Type B 
Connector 



a a 
x z 

CO (ft 

a a 




SDM-USB-QS-S 



GND GND 



S USBDP 


raft 


f\ USBDM 


DCDK 


B GND 


dsrE 


-Svcc 


DATAJN E 


§ SUSPJND 


DATA_OUT K 


§ RXJND 


RTSK 


9 TXJND 


CTSK 


;D485_TX 


DTR[]j 



16 
15 
14 
13 
12 
11 
10 
9 



—I 



Figure 8: USB Bus Powered Schematic 

The USB specification has strict allowances for using power from the bus. A 
device is allowed to use 100mA before enumeration, 500mA during normal 
operation, and 500|iA in suspend mode. A descriptor stored in the EEPROM will 
tell the host how much current the device will pull from the bus so that the host 
can allocate the appropriate power. The modules come programmed for 100mA, 
but if the final product will draw more than this then the device descriptors will 
need to be changed, as described in the next section. 

CHANGING THE DEVICE DESCRIPTORS 

The QS can be customized to display your product's name, manufacturer name, 
and to use different Product Identifiers (PID) and Vendor Identifiers (VID). This 
allows an end user to see the final product's name in their Windows Device 
Manager and when the hardware is first loaded. The PID and VID are set by the 
USB Implementers Forum and should not be changed unless the final product 
has gone through the certification process and received its own unique IDs. 

The Manufacturer, Description, and Serial Number strings can all be modified 
using the Linx Programming Software, which is included in the module's 
development system. This easy-to-use software will reprogram the module via 
the USB bus and can be done as a part of the final testing procedure. 

Once the module is reprogrammed some modifications to the driver files may be 
necessary. If a VID and PID other than the default Linx numbers are used these 
numbers will need to be added to the files. This requires modifying several lines 
in the .inf files and is described in detail in the programmer user manual. 
Modifying the name displayed by the Windows Device Manager requires 
changing only one line, also described in the programmer user manual. 

Note: when these drivers are installed on a system with Windows XP an error message 
may be displayed stating that these drivers are not certified and could potentially crash the 
system. As long as no other changes are made to the .inf files, this should not be a 
concern. 



Page 8 



TYPICAL APPLICATIONS 



There are many potential uses for the QS Series modules, but three will be 
described here. Figure 9 shows the QS and a MAX213 RS232 level converter 
IC from Maxim. This creates a USB-to-RS232 converter that supports all of the 
standard handshaking lines. Similarly, RS485 or RS422 level converter chips 
could be used for designs requiring those standards. 



0.1 uF J 
16V 1 



DTR> 



_BTS. 



< PCD I 



DSR I 



cu 


VCC 


V+ 


C1- 
C2+ 


MAX213 


V- 


C2- 






T1« 




T1out 


T2» 




T2ojt 


T3» 




T3our 


T4in 




T4om 


R1ojt 




Ml 


R2our 




R2m 


R30UT 




R3i» 


R4o^ 




R4m 






R5™ 


EN 

SHDN 


GND 






SDM-USB-QS-S 

USBDP Rl 

USBDM DCD 

GND DSR 

VCC DATAJN 

SUSPJND DATA_OUT 

RXJND RTS 

TXJND CTS 

485„TX DTR 



< DCD2~l 



I TX DATA2 >- 
I RTS2 >- 



<RX DATA2~1 

c 



I DTR2> — 



~Ri2~l 




Figure 9: RS232 To USB Converter 

The QS Series modules can be used with Linx RF modules to create a wireless 
link between two PCs. Figure 10 shows a design using the ES Series RF 
modules. One potential feature not shown in the schematic below is that one of 



the output lines of the QS module, RTS or [ 
lines of the RF modules enabling the host to turn the RF modules on and off. 



VCC 2[ 




TXM-XXX-ES 

]PDN ANTD 
JLVLADJ GNDfj 

jvcc lowvdetC 

JGND /CLKSELC 
1DATA /CLKP 



SDM-USB-QS-S 



U USBDP 


Rl[t 


U USBDM 


DCD0 


3 GND 


DSRE 


El VCC 


DATAJN E 


3 SUSPJND 


DATAJ0UT Q 


3 RXJND 


RTSG 


E! TXJND 


CTSO 


3485JX 


DTRG 



TX Side 




RX Side 



Figure 10: Wireless Modem Using The Linx ES Series RF Modules 



Page 9 



TYPICAL APPLICATIONS (CONT) 



Figure 11 below shows the QS module connected to a microprocessor. This is 
the design used in the QS Master Development Kit and the documentation for 
the kit describes the connections and software. 



USB Type B 
Connector 



RA2/AN2 

RA3/AN3 

RA4/AN4 

MCLR/VPP 

GND 

RBO/irn" 

RB1 



RA1/AN1 
RAO/ANO 
RA7 
RA6 
VCC 
RB7 

RB5/TX 



PIC16F88 



GND - 
DAT+ - 
DAT- ■ 



SDH-USB-QS-S 



vcc_j 



] USBDP 
USBDM 
GND 



RID 

dcdD 

DSHD 
DATAJN D 

5 hsuspjnd data-out d 
W^-^-Btx.ind 



8 § 485_TX 



VCC 

RTs 3 11 m ™ 
CTs 3 10 
DTR[ 9 *S 



Figure 11: Interface With A Microprocessor 



SOFTWARE CONSIDERATIONS 



The host application can access the QS module in two ways. First is through 
Virtual COM Port drivers. These drivers make the QS appear as an extra COM 
port on the host PC. This allows the application to use standard writes and reads 
to a serial port and the drivers will redirect data to the USB device. 

Second are a series of custom functions supported by the direct driver .dlls. 
These functions are also described in the Programmer's Guide where examples 
are given in both Visual Basic and C. The Programmer's guide can be 
downloaded from the Linx web site (www.linxtechnologies.com). 

In addition to the Programmer's Guide, the QS Master Development Kit (MDEV- 
USB-QS) includes example software and sample system source code. This 
source code provides the driver function declarations, examples of how to use 
the functions in a program, and other code that may be of use. 



Page 10 



ON-LINE RESOURCES 



LINX 

M l TECHNOLOGIES 
IHIII illHIII II II' EM 




www.linxtechnologies.com 

• Latest News 

• Data Guides 

• Application Notes 

• Knowledge Base 

• Software Updates 

If you have questions regarding any Linx product and have Internet access, 
make www.linxtechnologies.com your first stop. Our website is organized in an 
intuitive format to give you the answers you need in record time. Day or night, 
the Linx website gives you instant access to the latest information regarding the 
products and services of Linx. It's all here: manual and software updates, 
application notes, a comprehensive knowledge base, FCC information and much 
more. Be sure to visit often! 



www.antennafactor.com 

The Antenna Factor division of Linx offers 
a diverse array of antenna styles, many of 
which are optimized for use with our RF 
modules. From innovative embeddable 
antennas to low-cost whips, domes to 
yagi's, and even GPS, Antenna Factor 
likely offers or can design an antenna to 
meet your requirements. 




W£ l/ALUf OF CONNECTIONS 
www.con nectorcity.com 

Through its Connector City division, Linx offers a wide 
selection of high-quality RF connectors, including FCC- 
compliant types such as RP-SMAs that are an ideal 
match for our modules and antennas. Connector City 
focuses on high-volume OEM requirements, which 
allows standard and custom RF connectors to be offered 
at a remarkably low cost. 





Page 1 1 



( 




TECHNOLOGIES 



WIRELESS MADE SIMPLE 



iiiiii 

U.S. CORPORATE HEADQUARTERS: 



LINX TECHNOLOGIES, INC. 

575 S.E. ASHLEY PLA CE 
GRANTS PASS, OR 97526 

PHONE: (541) 471-6256 
FAX: (541) 471-6251 
http://www.linxtechnologies.com 



Disclaimer 



Linx Technologies is continually striving to improve the quality and function of its products; for 
this reason, we reserve the right to make changes without notice. The information contained in 
this Data Sheet is believed to be accurate as of the time of publication. Specifications are based 
on representative lot samples. Values may vary from lot to lot and are not guaranteed. Linx 
Technologies makes no guarantee, warranty, or representation regarding the suitability or 
legality of any product for use in a specific application. None of these devices is intended for 
use in applications of a critical nature where the safety of life or property is at risk. The user 
assumes full liability for the use of product in such applications. Under no conditions will Linx 
Technologies be responsible for losses arising from the use or failure of the device in any 
application, other than the repair, replacement, or refund limited to the original product purchase 
price. Some devices described in this publication are patented. Under no circumstances shall 
any user be conveyed any license or right to the use or ownership of these patents. 



© 2004 by Linx Technologies, Inc. The stylized 
Linx logo, Linx, and "Wireless made Simple" 
are the trademarks of Linx Technologies, Inc. 
Printed in U.S.A.